CO; (Cp2Fe)(BF4) in methanol; dichloromethane Dissolving of complex in CH2Cl2 under CO, dissolving of (Cp2Fe)(BF4) in MeOH under CO, cooling (-78°C) of both solns., stirring (10 min), addn. of CH2Cl2 soln. to MeOH soln., stirring (2 h, -78°C), warming to room temp.; Evapn., dissolving in CH2Cl2, filtering through Al2O3, vol. redn., chromy. (SiO2, hexane/Et2O) yields first yellow band of ferrocene, then the alkenyl ester as pale yellow oil, IR, (1)H NMR, (13)C NMR, MS, elem. anal.;

With  CO in  dichloromethane  Cooling (-78°C) of solns. of (CpFeCO(POPh)3)(eta.1-(E)-C(CH2OMe)C(Me)Ph and (Cp2Fe)(BF4), stirring (20 min, CO, 1 atm), addn. of (Cp2Fe)(BF4 in CH2Cl2 to alkenyliron complex by CO-pressure, stirring (45 min), removing from cold bath, stirring.; Filtering through Al2O3 , evapn., chromy. of oil on Al2O3 (eluant: hexane/CH2Cl2) yields yellow oil, elem. anal.;